Gas turbine engines, as well as other turbine based assemblies, utilize a compressor section that compresses a fluid, a combustor that mixes the fluid with a fuel and ignites the mixture, and a turbine section across which the resultant combustion gasses are expanded. The expansion of the combustion gasses drives rotors within the turbine section to rotate. The turbine rotors are mechanically connected to a shaft, and rotation of the turbine rotors drives rotation of the shaft. The shaft is, in turn, connected to rotors within the compressor section and drives rotation of the rotors in the compressor.
In a typical turbine based assembly, each of the rotors includes a radially inward rotor disk with multiple rotor blades protruding radially outward from the rotor disk. Due to the extreme temperatures encountered by the rotor blades, the rotor blades are actively cooled by passing a cooling fluid through internal passages within the rotor blade.
Rotor blades including such cooling passages are frequently created using an investment casting process, where a rotor blade is cast around a destructible core. Once the cast has cooled, the destructible core is destroyed and removed from within the rotor blade, leaving one or more internal cavities that form the cooling passages.